Apparatus for grinding and lapping annular sealing faces

ABSTRACT

In an apparatus for grinding and lapping annular sealing faces (25) in valves, slides and the like, a driven tool plate (4) carries freely rotable grinding and lapping heads (21) of which the axes are parallel to the rotary axis of the tool plate (4). In an eccentric bearing hole (15) of the tool plate (4), there is a circular bearing plate (10) which is rotable relatively to the tool plate (4) and can be securely connected in the desired rotary position to the tool plate (4). A drive pin (5) is eccentrically connected to the bearing plate (10) for rotation therewith (FIG. 3).

This application is a continuation of application Ser. No. 555,556,filed Nov. 28, 1983, and now abandoned.

The invention relates to an apparatus for grinding and lapping annularsealing faces in valves, slides and the like, comprising a mountingsecurable to the workpiece and having on one side a drive and on theother side a rotatable tool plane which is coupled to the drive by atransmission element and carries a series of freely rotatable grindingor lapping heads with axes parallel to the tool plate axis, the headsbeing radially adjustable relatively to the tool plate.

Such apparatuses are used particularly to grind and lap the sealingfaces in valves, slides, valve plates, slide wedges, slide plates andflanges in their built-in condition. It is known that with the rotationof the tool plate such grinding or lapping heads are rotated byfrictional forces acting upon them, if said frictional forces lead to apositive or negative moment with respect to the axes of said heads. Inthis way, any evidence of wear and deposits at these faces is removedwithout having to undo the workpieces from where they are built in andto dismantle them.

In apparatuses of this kind used hitherto, the diameter of theindividual grinding or lapping heads is selected to be larger than theradial width of the annular face to be treated. This can makereplacement of the tool heads necessary so as to adapt them to theparticular surface to be treated.

It is the problem of the present invention to provide an apparatus ofthe aformentioned kind with a simple adjustment permitting tool heads tobe used for the treatment of annular sealing faces having a radial widthgreater than the diameter of the tool heads.

This problem is solved according to the invention in an apparatus of theaforementioned kind in that the tool plate has a bearing hole which isoffset from its midpoint and in which a circular bearing plate isadjustably mounted, a drive pin which is coupled to the transmissionelement being secured off-centre to the bearing plate for rotationtherewith.

By setting the bearing plate in relation to the bearing hole of the toolplate, the fulcrum of the plate is changed. Consequently, the spacing ofthe individual tool axes from the rotary axis is varied. One can thusensure that the individual tool heads turn on circular tracks of whichthe diameters are not equal. In this way, the tool heads can sweep overan annular sealing face of which the radial width is larger than thediameter of the tool heads.

This also results in an optimum grinding pattern with a high degree ofplaneness of the treated surface. The reason for this is that thegrinding or lapping grooves intersect at a multiplicity of differentangles.

The apparatus of the invention can be constructed so that theeccentricity of the bearing hole relatively to the centre of the toolplate is equal to the eccentricity of the point of engagement of thedrive pin on the bearing plate in relation to this plate. By means ofthis arrangement, it is possible for setting purposes to arrange thepoint of engagement of the drive pin centrally of the tool plate.

Further, the apparatus can be constructed so that the bearing holedefines a shoulder abutted by a counter-shoulder of the bearing plate.

Finally, the construction may be such that the bearing plate isscrew-connected to the tool plate. Tapped holes are provided in thebearing plate or in the tool plate and the respective other part isprovided with corresponding push-through holes. It is then possible tooffset the bearing plate in relation to the tool plate corresponding tothe pitch of the screwthread. The eccentricity of the drive for the toolplate can be then changed in corresponding steps.

One example of the appartus of the invention will now be described withreference to drawings, wherein:

FIG. 1 is a side elevation of one embodiment of the apparatus accordingto the invention in conjunction with a valve housing to be machined;

FIG. 2 is a fragmentary elevation of the tool plate according to theinvention;

FIG. 3 is a section on the line 3--3 in FIG. 2, the mounting for thedrive of the tool plate being indicated, and

FIG. 4 is a fragmentary elevation of the tool plate taken in thedirection of the arrow 4 in FIG. 3.

The apparatus of the invention comprises a mounting 1 by means of whichit can be secured to a workpiece in a manner which need not here bedescribed in detail, the workpiece having an annular sealing face 25which is to be ground or lapped. The mounting 1 carries a drive 2 andcomprises tubes 3 which connect the drive 2 to a tool plate 4. Atransmission element (not shown) extends through the tubes 3 andtransmits rotary motion from the drive 2 to a drive pin 5. The latter ismounted in a lower end member 6 of the mounting 1.

The drive pin 5 is spherical at the end 7 projecting from the end member6 and equipped with two diametral pins 8 extending transversely to theaxis of the drive pin 5. The pins 8 serve to transmit the rotary motionof the drive 2 and thus of the drive pin 5.

The spherical end 7 of the drive pin 5 engages in a corresponding pan 9of a bearing 10. The pins 8 come to lie in complementary recesses of thepan 9.

The bearing plate 10 has a section 11 followed by a section 12 of largerdiameter. The section 11 thus forms a radially projecting flange 13 anda shoulder in which tapped holes 26 are provided. The bearing plate 10is circular, the axis of the pan 9 being offset by a distance a from thecentral axis 14 of the bearing plate 10.

The bearing plate 10 is received by a complementary bearing hole 15 inthe hub zone of the substantially rotationally symmetrical tool plate 4.The axis 15a of the bearing hole 15 is offset by the distance a from thecentral axis 14 of tool plate 4. The tool plate 4 contains holes 17 forreceiving screws 18 which engage in the tapped holes 26 of bearing plate10.

After loosening the screws 18, the bearing plate 10 can be turned in thebearing hole 15. Depending on the pitch of the holes 17/26 or screws 18arranged on a circle, the bearing plate 10 can be fixed by the screws 18in a series of positions relatively to the tool plate 4.

The section 11 of the bearing plate 10 is provided with markings 19which co-operate with opposite markings on the tool plate 4. Thesemarkings indicate when the bearing plate 10 is so arranged in relationto the tool plate 4 that the axis of the tool plate 4, i.e. theeccentricity is zero. The markings also permit the ecentricity of thedrive shaft to be set in relation to the axis of the tool plate 4.

With a rotationally symmetric construction, the tool plate 4 is providedwith radially extending grooves 20 for receiving freely rotatablelapping or grinding heads 21.

When the apparatus here in question is used, the bearing plate 10 isfirst set to zero eccentricity. At this setting, the tool plate 4 isaligned in position in relation to the annular sealing face 25 to bemachined. Subsequently, the bearing plate 10 is turned in the bearinghole 15 to set the desired eccentricity so that the individual lappingor grinding heads 21 are differently spaced from the fulcrum of the toolplate 4.

I claim:
 1. Apparatus for grinding and lapping annular sealing faces invalves, slides and the like, comprising a mounting securable to theworkpiece and having on one side a drive and on the other side a rotabletool plate which is coupled to the drive by a tranmission element andcarries a series of freely rotatable grinding or lapping heads with axesparallel to the tool plate axis, the heads being radially adjustablerelatively to the tool plate, the tool plate (4) has a bearing hole (15)which is offset from its mid-point and in which a circular bearing plate(10) is adjustably mounted, a drive pin (5) which is coupled to thetransmission element being secured off-centre to the bearing plate forrotation therewith.
 2. Apparatus according to claim 1, wherein theeccentricity of the bearing hole (15) relatively to the centre of thetool plate (4) is equal to the eccentricity of the point of engagementof the drive pin (5) on the bearing plate (10) in relation to thisplate.
 3. Apparatus according to claim 1 or claim 2, wherein the bearinghole (5) defines a shoulder (13) abutted by a counter-shoulder of thebearing plate (10).
 4. Apparatus according to claim 1 wherein thebearing plate (10) is screw-connected to the tool plate (4). 5.Apparatus according to claim 1 or 2 wherein the bearing plate isscrew-connected to the tool plate. .Iadd.
 6. Apparatus for grinding andlapping annular sealing faces in valves, slides and the like, saidapparatus comprising:a mounting structure securable to a workpiece;drive mechanism including a rotary drive pin carried by the structure; arotatable tool plate carried by the structure; a series of freelyrotatably grinding or lapping heads carried by said tool plate withtheir axes of rotation parallel to the axis of rotation of the plate,said heads being radially shiftable relative to the plate; said platehaving a bearing hole therein; a circular bearing plate rotatablymounted in said bearing hole; a joint interconnecting said drive pin andsaid bearing plate for rotation of the plate with the pin; the point ofconnection between said drive pin and said plate being offset relativeto the center of the bearing plate. .Iaddend. .Iadd.7. Apparatus as setforth in claim 6 wherein said bearing hole is offset from the axis ofrotation of the tool plate. .Iaddend. .Iadd.8. Apparatus as set forth inclaim 7 wherein the offset of the bearing hole relative to the mid-pointof the tool plate is equal to the offset of the said point of connectionrelative to the center of the bearing plate. .Iaddend. .Iadd.9.Apparatus as set forth in claim 6 wherein said joint comprises auniversal joint. .Iaddend. .Iadd.10. Apparatus as set forth in claim 9wherein said joint comprises interengaged ball and socket elements..Iaddend. .Iadd.11. Apparatus for grinding and lapping annular sealingfaces in valves, slides and the like, said apparatus comprising:meansfor mounting the apparatus on a workpiece; a drive mechanism including arotatable drive pin; a tool plate mounted for rotation about an axiswhich extends through the plane of the plate, said plate having abearing hole therein which is offset from said axis; a series of freelyrotatably grinding or lapping heads mounted on the plate for rotationabout individual axes which are esentially perpendicular to the plane ofthe plate; a bearing plate adjustably mounted in said hole and securablethereto for rotation together with the tool plate about said axis; andmeans operably connecting the drive pin and the bearing plate forrotation together, the point of connection on the bearing plate beingoffset relative to the center of the hole. .Iaddend. .Iadd.12. Apparatusas set forth in claim 11 wherein said bearing hole and said bearingplate are circular, said plate being mounted for rotation in said holefor accomplishing said adjustment. .Iaddend. .Iadd.13. Apparatus as setforth in claim 10 wherein said means for connecting the transmissionelement and the bearing plate comprises a universal joint. .Iaddend..Iadd.14. Apparatus as set forth in claim 13 wherein said bearing holeand said bearing plate are circular, said plate being mounted forrotation in said hole for accomplishing said adjustment. .Iaddend..Iadd.15. Apparatus as set forth in claim 13 wherein said universaljoint comprises interengaged ball and socket elements. .Iaddend..Iadd.16. Apparatus for grinding and lapping annular sealing faces invalves, slides and the like, said apparatus comprising:a mountingstructure securable to a workpiece; drive mechanism including a rotarydrive pin carried by the structure; a rotatable tool plate carried bythe structure; a series of freely rotatably grinding or lapping headscarried by said tool plate with their axes of rotation parallel to theaxis of rotation of the plate; said plate having a bearing hole therein,said hole being offset from the axis of rotation of the plate; acircular bearing plate rotatably mounted in said bearing hole; a jointinterconnecting said drive pin and said bearing plate for rotation ofthe plate with the pin; the point of connection between said drive pinand said plate being offset relative to the center of the bearing plate..Iaddend.